Forming small flexible containers

ABSTRACT

Small containers are filled and formed from a large preformed and presterilized container, which incorporates communicating compartments. The volume of contents of each compartment are equalized by pressure application and then the compartments are sealed off and severed to form individual containers.

FIELD OF THE INVENTION

This invention relates to a method of forming small flexible containers.

BACKGROUND OF THE INVENTION

Sachets of flexible film forming material are known. In the foodpackaging industry it has been conventional to "form, fill and seal".That is the individual flexible container is formed, it is then filledwith food product and the container sealed. This means that one fillinghead can fill only one container at a time, For small containersproduction times are increased because the time taken to bring thecontainer into alignment with the filling head and then to remove it, issignificant and the volume of product filled from any filling head iscorrespondingly reduced when smaller containers are filled.

For consumer use and for applications where measured quantities ofproduct are desirable in disposable containers there is a demand forsmall volume containers.

The cost to food packagers of using a form, fill and seal method asopposed to buying preformed packages and only filling and sealing isalso significant. However preformed packages especially for smallvolumes are difficult to handle. Further where aseptic techniques areused sterilization becomes a problem. Thus in these applications theform, fill and seal method has been seen to be advantageous because asterilization step can be carried out between the forming and fillingsequences.

A number of proposals have been made to increase the volume ofproduction of small containers using the form, fill, seal method. U.S.Pat. No. 4,517,787 is a recent example and U.K. No. 2054511 is anexample of forming and filling a plurality of small compartments whichare subsequently separated to form individual packages.

SUMMARY OF THE INVENTION

It is an object of this invention to provide a more effective means ofincreasing the volume of production on filling small containers and toprovide an alternative means to the capital intensive form, fill andseal method.

To this end the present invention provides a method of forming filledflexible containers comprising:

filling a large flexible container having heat sealable walls with afluid product,

applying to the container a template means to divide the container intoseparate communicating compartments by bringing opposed walls of thecontainer into contact,

distributing the content of the fluid product between said compartmentsby varying the pressure applied to the container to obtain a desireddistribution, and

heat sealing the opposed walls of the container together to form sealedfilled compartments which are capable of separation into individualfilled containers.

It is possible by this method to use a pre-sterilized container of thekind described in Australian patent No. 552,032. It can be filled andsealed and then stored or transported prior to being further handled toform the separate small packages. This method ensures that higher volumethroughputs on the filling machine can be achieved. Aseptic packaging isalso a feature of this method.

A further aspect of this invention is to provide a preformed flexiblecontainer with preformed intercommunicating compartments. Thecompartments may be formed by heat sealing portions of the walls of thelarger container in a pattern which creates a series ofintercommunicating compartments. For example in a rectangular envelopetype container with an inlet at one end heat seals extending across thewidth of the container from the edge seams create a series ofrectangular compartments. If a portion on line from the inlet is leftunsealed a fill channel is formed. If this fill channel is down thecentre of the envelope then it is possible to form two series ofcompartments.

Once the compartmented container is filled and sealed the final step ofsealing the individual compartments can be performed at any desiredtime. To do this it is necessary to ensure a correct distribution offluid content between the compartments. It is not necessary for these tobe of the same size or for them to be filled to the same extent. Thevolume of product in each compartment is related to the pressure in eachcompartment and by varying the applied pressure it is possible to obtainany desired volume distribution between the compartments.

Fluid flow between the compartments is hindered by any creasing orkinking of the flexible package. By tensioning the package in thedirection of the intercommunicating passages flow between compartmentsis facilitated. Thus during the step of distributing product betweencompartments the container envelope is preferably tensioned. This can bedone by stretching or by supporting the envelope along the linesseparating the compartments which are lateral to the intercommunicatingpassages. The weight of product then tensions the flexible containermaterial to provide a crease free passage between compartments. Thisthen facilitates the final heat sealing step whereby the passages areclosed and separate sealed compartments are formed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 of the drawings illustrate two embodiments of thisinvention and FIG. 3 is a schematic representation of the apparatus usedto distribute product between compartments and to heat seal them.

FIGS. 4, 5, 6 and 7 illustrate an alternative method of filling andforming utilizing the package construction shown in FIG. 2.

In FIG. 1 a simple 4 compartment package is illustrated. This comprisesan envelope 5 having a filling gland 6, an edge seal 7 and lateral heatseal seams 8. The passage 9 allows product entering through gland 6 toenter all compartments formed by the seams 8. The envelope 5 and thegland 6 are as described in Australian patent No. 552,032.

FIG. 2 is a variation of the package shown in FIG. 1. The envelope 11has the filling gland 12 and edge seams 13 as previously described. Thelateral seams 14 form two series of compartments on either side of acentral passage 15. Two of the compartments are shown as havingpreformed seams 17 which are shaped to assist in product equilibrationas described below. These seams are also shaped to enable easierdispensing of contents through the outlet 18 which in the separatedcontainer can be slit to allow pouring.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 3 the package of FIG. 1 is schematically illustrated in theapparatus which achieves final product distribution between thecompartments. The container 5 is supported by a corrugated base 21 alongeach lateral seam 8 by individual ribs 22. This opens up the channel 9in the package 5 and allows free product flow. It also ensures that thewalls of the envelope will have flat contact to facilitate good heatsealing. To obtain equal distribution of contents to each compartmentthe plate 24 applies pressure to the envelope 5. If desired individualpressure plates can be provided for each compartment and pressuremeasured to achieve a volume distribution calibrated on the measuredpressure. Once the desired distribution is achieved the heat sealingrods 25 are lowered to heat seal the walls of the envelope together toextend seams 8 so that they extends from one edge seam 7 to the otherand so form 4 separate compartments.

There is no limit on the number of compartments which may be formed.After heat sealing the compartments are separated by cutting along thecentre of each seam 8 or 14. Alternatively the partition seals 8 or 14may be partially or fully present or perforated to accommodate thedecrease in horizontal length of the middle section when the multi pouchcontainer 5 is filled. Where seals 8 and 14 are perforated these willsplit once the container is in the volume equalizing device of FIG. 3. Afurther heat seal is usually effected to enable the gland 6 to bediscarded.

If the edge seals 7 of FIG. 1 and 13 of FIG. 2 are gussetted when theindividual containers are sealed and separated this gussetted edge willform a base enabling the containers to stand upright.

The size of the compartment forming machine need only be half the lengthof the container envelope as the corrugated base increases tension onthe envelope to allow easy flow along passage 9 and in so doingdecreases the effective length of the envelope.

The embodiment shown in FIGS. 4 to 7 represents schematically theforming of the package shown in FIG. 2.

The filled bag 11 is draped over a central rail or saddle 30 and thefilling gland 12 is secured by clamp 31 and the end of the bag 11 issecured at seam 13 by clamp 32 as shown in FIG. 4.

Subsequently as shown in FIG. 5 side pressure is applied by the pressureplates 33 and 34 to equalize the fluid level across all the compartmentsbetween the seams 14. Once equilibrium has been achieved the sidepressure from plates 33 and 34 is released.

Next, as shown in FIG. 6 tension is applied between clamps 31 and 32 toremove creases which may have formed across passage 15. Heat sealingbars 35 and 36 are then applied against the sides of the bag to seal thetop of each compartment along the lines bordering passage 15 andintersecting the ends of the seams 14.

The compartments may each then be separated by severing along the centreof the seams 14 and the newly formed topseals bordering passage 15.

As shown in FIG. 7 after the severing operation only passage 15 and thefilling gland 12 remain and these can be released from clamps 31 and 32and discarded.

There is no restriction on the shape of size of the container or of thenumber, shape or size of compartments. The filling gland may be locatedat any convenient position either centrally of the container or at itsperiphery. An alternative to a rectangular container is a circularcontainer with a central gland and radial seams to form compartments.

Thus it can be seen that the present invention provides a unique meansof forming small fluid flexible packages whilst maintaining highproduction rates at the filling machine, eliminating the need to haveexpensive form, fill and seal machinery and also utilize aseptic fillingtechniques.

The claims defining the invention are as follows.

We claim:
 1. A method of forming filled flexible containerscomprising:filling a large flexible container having heat sealable wallswith a fluid product inserted into the container through a containerinlet, supporting the container along its length intermediate its sideedges so that opposite side portions of the container depend downwardlyon either side of the support, applying to the depending side portionsof the container a template means to divide the depending side portionsof the container into separate communicating compartments by bringingopposed walls of the container into contact, distributing the content ofthe fluid product between said compartments in each depending sideportion by varying the pressure applied to the depending side portionsof the container to obtain a desired distribution, and heat sealing theopposed walls of the depending side portions of the container togetherto form sealed filled compartments which are capable of separation intoindividual filled containers.
 2. A method as claimed in claim 1 whereinthe container inlet is located at one end of the supported length of thelarge flexible container, and including the step of tensioning thesupported length of the container in the direction of its length.